Solaris ships with everything you need, with the exception of the compiler itself. Solaris ships with the include files, make, an assembler, linker and libraries. All this stuff lives in /usr/ccs/bin (add it to your PATH before /usr/ucb if that's in your PATH as well) /usr/ccs/lib and /usr/include.
If you still can't find it, make sure you have the following packages installed on your system:
for tools (sccs, lex, yacc, make, nm, truss, ld, as): SUNWbtool, SUNWsprot, SUNWtoo for libraries & headers: SUNWhea, SUNWarc, SUNWlibm, SUNWlibms SUNWdfbh, SUNWcg6h, SUNWxwinc, SUNWolinc, SUNWxglh for 64 bit development: SUNWarcx, SUNWbtoox, SUNWdplx, SUNWscpux, SUNWsprox, SUNWtoox, SUNWlmsx, SUNWlmx, SUNWlibCx for ucb compat: SUNWsra, SUNWsrh
These packages are all on the Solaris 2.x CDs, except that some packages may only exist in some releases and not in others. Some packages may be on separate CDs, such as the "Desktop/CDE" CD, but all are part of the Solaris "bundle".